This invention relates generally to power converting systems, and more particularly to systems and methods for providing a multi-function power converting system including low and high voltage buses.
The increase in the cost of operating certain equipment, such as engine driven vehicles, and government standards associated with these types of equipment, has sparked a growth in the design and implementation of electrical-based components, such as electro-mechanical power sources and controllers. For example, in certain vehicles, selected parts, such as belts, pulleys, gear driven components, etc., may be controlled or replaced with electrical-based components. Such re-designing may enable a manufacture to reduce the cost of a vehicle by eliminating components, reduce costs associated with the wear and tear of these moving parts, and reduce emissions.
Typically, in systems that utilize electrical-based components, such as headlights for a vehicle, power may be supplied by an internal power source, such as a battery. These systems may also allow the battery to be charged from an external source through power conversion circuits. Further, these systems may also provide AC power to selected components by converting the DC power provided by the battery source through an inverter circuit. Although these systems provide versatile power supply and control capabilities, they are limited to low voltage applications. Further, the cost of these systems increases with each additional conversion function implemented because each function may be provided as a discrete component that may require corresponding support components, such as individual isolation transformers, converter components and controllers. Accordingly, typical systems that are designed to provide multiple power conversion capabilities may include redundant components dedicated to a particular conversion function.
One such system is described in U.S. Pat. No. 6,021,052, issued to Unger et al. This patent describes a power converter system that implements a plurality of controllers for various modes of operation. The system may supply energy to a DC bus from a load balancing storage element when the voltage of the DC bus is decreasing and store energy from the DC bus in the storage element when the voltage of the DC bus is increasing. Further, the system may selectively transfer energy from the DC bus to an AC port. Although the power converting system described by Unger et al. may provide multiple conversion functions, these functions are selectively performed and controlled by dedicated controlling circuitry. Accordingly, the system described by Unger et al. results in a system that is more costly and is limited to selective modes of operation associated with a low voltage DC bus and AC ports.
Methods and systems consistent with certain features of the present invention are directed to solving one or more of the problems set forth above.
In an aspect of the present invention, a multi-function system is provided that may include a high voltage DC bus, a low voltage DC bus, and a transformer connected between the high voltage DC bus and the low voltage DC bus. The system may be configured to simultaneously provide power from the low voltage DC bus to the high voltage DC bus and an AC load through the transformer. Further, the system may also simultaneously provide power from the high voltage DC bus to the low voltage DC bus and the AC load through the transformer. And, the system may simultaneously provide power from a shore power source to the AC load, and to the low voltage DC bus and high voltage DC bus through the transformer.
In another aspect of the invention, a system is provided that may include a high voltage bus, a low voltage bus, and a transformer disposed between the high voltage and low voltage buses. The system may also include a first inverter/rectifier circuit connected between the high voltage bus and a primary side of the transformer, a second inverter/rectifier circuit interconnected between the low voltage bus and a secondary side of the transformer, and an AC load connected to a tap positioned on the secondary side of the transformer. The system may be configured to selectively provide power simultaneously to the high voltage bus through the first inverter/rectifier circuit and power to the AC load through the tap. Further, the system may selectively provide power simultaneously to the low voltage bus through the second inverter/rectifier circuit and power to the AC load through the tap. Additionally, the system may selectively provide power simultaneously to the AC load from a shore power source and power to the low voltage bus through the second inverter/rectifier circuit and power to the high voltage bus through the first inverter/rectifier circuit.